Processes for converting natural gas to CO2 and electricity via so-called natural gas combined cycle (NGCC) processes are becoming increasingly important as power producers seek routes to reduce carbon dioxide emissions.
US 2008/0155984 discloses a process for producing power and partially capturing CO2 comprising stream reforming a mixture of hydrocarbon and steam at <800° C. to form a first reformate stream, subjecting the first reformate stream to the water-gas shift reaction to form a second reformate stream having an increased hydrogen content, removing a portion of CO2 from the second reformate stream to generate a third reformate stream (wherein <50% of the carbon in the first reformate stream is removed), combusting the third reformate stream in a gas turbine to generate power and an exhaust gas stream, utilizing heat in the exhaust gas stream in a heat recovery steam generator to generate steam, and using the steam to generate additional power.
This process has the drawback that the steam reforming reactions are endothermic and consume considerable amounts of energy that would better be converted to power. Indeed in the aforesaid US2008/0155984, the inventors have sought to overcome this drawback by performing the steam reforming reactions in the heat recovery steam generator. It is also not readily retrofitted into an existing NGCC plant.